1. Technical Field
The present invention relates in general to improved hard disk drive performance, and in particular to an improved suspension for hard disk drives. Still more particularly, the present invention relates to an improved, integrated gimbal design for a disk drive suspension.
2. Description of the Prior Art
Generally, a data access and storage system consists of one or more storage devices that store data on storage media such as magnetic or optical data storage disks. In magnetic disk storage systems, a storage device is called a direct access storage device (DASD) or hard disk drive (HDD), which includes one or more hard disks and an HDD controller to manage local operations concerning the disks. Hard disks are rigid platters, typically made of aluminum alloy or a mixture of glass and ceramic, covered with a magnetic coating. Typically, two or three platters are stacked vertically on a common spindle that is turned by a disk drive motor at several thousand revolutions per minute (rpm).
The only other moving part within a typical HDD is the head stack assembly. Within most drives, one read/write head is associated with each side of each platter and flies just above or below the platter""s surface. Each read/write head is mounted on a suspension to form a head gimbal assembly (HGA). The HGA is then attached to a semi-rigid arm apparatus which supports the entire head flying unit. More than one of such arms may be utilized together to form a single armature unit.
Each read/write head scans the hard disk platter surface during a xe2x80x9creadxe2x80x9d or xe2x80x9cwritexe2x80x9d operation. The head/arm assembly is moved utilizing an actuator which is often a voice coil motor (VCM). The stator of a VCM is mounted to a base plate or casting on which is also mounted the spindle supporting the disks. The base casting is in turn mounted to a frame via a compliant suspension. When current is fed to the motor, the VCM develops force or torque which is substantially proportional to the applied current. The arm acceleration is therefore substantially proportional to the magnitude of the current. As the read/write head nears the desired track, a reverse polarity signal is applied to the actuator, causing the signal to act as a brake, and ideally causing the read/write head to stop directly over the desired track.
Conventional disk drive suspensions are made as either two pieces including a load beam and a flexure, or as a single, integrated gimbal assembly. In order to increase the stiffness of the suspension and its dynamic performance, flanges are typically formed on the suspension. Unfortunately, the extra forming step changes the flatness of the suspension and increases its overall thickness, such that the dynamic performance of the suspension is downgraded. In addition, the two-piece suspension designs require an extra laser welding processing step to assemble the pieces together. This welding process requires additional tooling and introduces assembly tolerances as well. Moreover, the weld process tends to distort the suspension due to high welding temperatures, and degrades the dynamic performance and quality control for the suspension. Thus, an improved disk drive suspension design that overcomes the limitations of the prior art is needed.
An integrated suspension for a hard disk drive is formed as a single-piece flat assembly. The design eliminates the need for mechanical reinforcement such as flange forming, and requires no additional weld processing to form the functional portion of the assembly. A partial etch process is used to reduce local thicknesses in the gimbal and hinge areas to reduce the overall stiffness of the suspension. The proximal end structure of the suspension is also built by partial etching to achieve higher natural frequencies. The suspension design also incorporates built-in load/unload features and two-sided, opposite-facing limiters to limit slider displacement during the manufacturing process, loading/unloading, and non-operational shock environments.
Accordingly, it is an object of the present invention to provide improved hard disk drive performance.
It is an additional object of the present invention to provide an improved suspension for hard disk drives.
Still another object of the present invention is to provide an improved, integrated gimbal design for a disk drive suspension.